At each Mass, we're asked to give each other a sign of Christ's peace. For a long time, as a child, I misunderstood this as a promise of peace as opposed to violence - a handshake promise that I won't sock you in the nose this week.
Its appropriate, for me, that this Sunday's reading is the well-known passage on love from St. Paul. He mentions, several times, the difference between a childhood understanding and an adult understanding. While he is making an analogy to our earthly understanding compared to what we will know and experience in heaven, the face value of childhood-vs.-adulthood is still meaningful. As adults, we can update our understanding of the sign of peace.
We don't simply wish someone peace instead of violence, we wish that Christ's peace be with them. What is Christ's peace?
Jesus was hardly peaceful in the "keep quiet and don't cause trouble" sense of the word; just recall His visit to the temple in Jerusalem (Matt 21:12-13). The peace He had and wished for His disciples is spiritual peace - not freedom from outer violence but from inner turmoil. Christ's peace is the knowledge that, like St. Paul said, we are spiritual children. Whatever we think we need - physically, emotionally, or spiritually - God the Father knows how to care for us. Sometimes we have to accept "because I said so" as His children and find peace in knowing that our Father will provide. Christ put Himself in the Father's hands, even with His last words from the cross (Luke 23:46), and His peace will come when we can do the same.